NH2-Ga-MIL-53催化剂对Strecker反应的底物选择性 |
Substrate-Selectivity of Strecker Reaction Based on Amino-Functionalized Ga-MIL-53 Catalyst |
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摘要: 研究了金属有机骨架化合物NH2-Ga-MIL-53对多种N-苯基亚胺底物的Strecker反应的催化性能,研究结果表明:(1)NH2-Ga-MIL-53具有高度催化活性和良好的底物普适性;(2)亚胺底物上取代基的电子效应是影响催化反应速率的关键因素,在亚胺底物上引入给电子取代基团(如甲氧基和苯基)可以加快反应速率,引入吸电子取代基团(如三氟甲基和硝基)可降低反应速率;(3)亚胺底物上取代基的位置对于催化反应速率同样具有重要影响,在亚胺底物的邻位引入甲氧基取代基团时,反应速率加快得最明显;(4)作为非均相催化剂,NH2-Ga-MIL-53可循环使用9次而不失活且保持骨架结构不变;(5)NH2-Ga-MIL-53和Ga-MIL-53催化性能的对比结果表明,NH2-Ga-MIL-53结构中的氨基可以作为路易斯碱活性中心协同路易斯酸催化中心(Ga3+)有效促进strecker反应的进行。此外,由NH2-Ga-MIL-53、六水合硝酸镓和2-氨基对苯二甲酸对Strecker反应的催化效果的对比可知,NH2-Ga-MIL-53的孔结构是提高反应产物专一性的重要因素。 |
关键词: 金属有机骨架配合物 镓 非均相催化 Strecker反应 底物选择性 |
基金项目: 国家自然科学基金(No.21171065,21201077和21401005)资助项目 |
Abstract: This work focuses on Strecker reactions catalyzed by metal-organic framework (MOF) of amino-functionalized Ga-MIL-53 (NH2-Ga-MIL-53) in regard to substrates of a series of N-Ph aldimines, and the results showed that:(1) NH2-Ga-MIL-53 exhibited excellect catalytic activity and good univisality among various substrates; (2) the electronic effect of substituents for substrates primarily affects the catalytic reaction rate, and the electron-donating substituted groups (i.e., MeO, Ph) and electron-withdrawing substituted groups (i.e., CF3, NO2) show promotion and suppression effects on the reaction, respectively; (3) the substituted position of substituents in respect of substrates secondarily influences the reaction rate, and the ortho-substituted MeO group perform the strongest promotion effects on the reaction; (4) as a heterogeneous catalyst, NH2-Ga-MIL-53 can be reused for 9 runs without obvious loss of conversion efficiencies and collapse of MOF structure; (5) contrasting the catalytic performances between NH2-Ga-MIL-53 and Ga-MIL-53, it is indicated that the amino groups of NH2-Ga-MIL-53 can be served as Lewis base moieties, facilating the reaction according to Lewis acid-base synergistic mechanism. Furthermore, comparing the catalytic effects among NH2-Ga-MIL-53, Ga(NO3)3·6H2O and 2-aminoterephthalic acid, it is concluded that the pore structure of NH2-Ga-MIL-53 framework plays a significant role in avoiding the side reactions with respect to Strecker reaction. |
Keywords: metal-organic frameworks gallium heterogeneous catalysis Strecker reaction substrate-selectivity |
投稿时间:2019-09-26 修订日期:2019-11-27 |
摘要点击次数: 2011 |
全文下载次数: 801 |
王鹏程,吴淑杰,单梁,姜岩松,范勇,王莉,陈晓东,徐家宁.NH2-Ga-MIL-53催化剂对Strecker反应的底物选择性[J].无机化学学报,2020,36(3):547-554. |
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